Intelligent roaming system with over the air programming

ABSTRACT

An apparatus for selecting a preferred wireless carrier from a plurality of wireless carriers for use by a mobile station when the mobile station is roaming outside of a home market area is provided. The apparatus comprises a database, a generator, and a data providing device. The database stores preferred wireless carrier identities for a plurality of market areas based upon predetermined classes of service, predetermined national accounts, and predetermined home market areas. The generator generates a list of the preferred wireless carrier identities based upon a selected class of service, a selected national account, a selected home market area of the mobile station. The data-providing device transmits the generated list to each mobile station designated with the selected class of service, selected national account and selected home market area. The list of preferred wireless carriers may be based upon the roaming wireless carriers&#39; airtime rates and services provided for each of the plurality of market areas. The list may also be based upon a preferred or required air interface technology. The generator may update the list of preferred wireless carriers when one of the plurality of wireless carriers changes a communication characteristic (such as roaming airtime rates the wireless carrier charges for a market area, and services the wireless carrier offers to a market area). The data-providing device provides the updated list of preferred wireless carrier identities to each mobile station previously provided with the list the generator updated.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of telecommunications. Moreparticularly, the present invention relates to cellular, PersonalCommunications Services (PCS) and other wireless network systems, andmobile stations having intelligent roaming and over-the-air programmingfeatures.

2. Related Application Information

The present disclosure relates to subject matter contained in U.S.patent application Ser. No. 08/828,172 (filed on Mar. 18, 1997), whichis expressly incorporated herein by reference in its entirety.

3. Background and Material Information

The use of wireless or mobile communication devices has increasedgreatly in recent years. Mobile and cellular telephones have enabledmobile station users to roam over large geographic areas whilemaintaining immediate access to telephony services. Mobile stationsinclude portable units, units installed in vehicles and fixed subscriberstations. Mobile stations comprising cellular telephones or wirelesshandsets are operable in cooperation with cellular or PersonalCommunications Services (PCS) communications systems. Cellularcommunication systems (wireless carriers) typically provide service to ageographic market area by dividing the area into many smaller areas orcells. Each cell is serviced by a radio transceiver (i.e., atransmitter-receiver base station or cell site). The cell sites or basestations may be connected to Mobile Telephone Switching Offices (MTSOs)or Mobile Switching Centers (MSCs) through landlines or othercommunication links, and the MTSOs may, in turn, be connected vialandlines to the Public Switched Telephone Network (PSTN).

FIG. 1 illustrates the basic components of a conventional cellularnetwork. As shown in FIG. 1, a mobile station 38 may place or receivecalls by communicating with a cell site 30 or a cell site 40, dependingupon the geographic location of the mobile station and the cell coveragearea that is provided by each cell site (i.e., cell coverage area 35 ofcell site 30 or cell coverage area 45 of cell site 40). For purposes ofillustration, mobile station 38 is depicted in FIG. 1 as being able tocommunicate with either cell site 30 or cell site 40, even though themobile station is not illustrated as being located within cell coveragearea 35 or cell coverage area 45. Under normal operating conditions, theextent to which mobile station 38 will be able to communicate with cellsite 30 or cell site 40 will depend on the geographic location of themobile station and the size of the cell coverage area of each cell site.Further, although only two cell sites are depicted in FIG. 1, the entirecellular network may include, for example, more than two cell sites. Inaddition, more than one cell site may be connected to each MTSO.

Mobile station 38 may include a conventional cellular telephone unitwith a transceiver and antenna to communicate by, for example, radiowaves with cell sites 30 and 40. Various air-interface technologies maybe implemented to facilitate communication between the mobile stationand the cell sites. In addition, various service offerings may be madeavailable to mobile station users. Cell sites 30 and 40 may both includea radio transceiver and be connected by landlines 16 or othercommunication links to MTSOs 24 and 28. The PSTN 12 is also connected toeach MTSO 24 and 28 by landline 16 or other communication links.

The MTSOs 24 and 28 may be conventional digital telephone exchanges thatcontrol the switching between the PSTN 12 and the cell sites 30 and 40to provide wireline-to-mobile, mobile-to-wireline and mobile-to-mobilecall connectivity. The MTSOs 24 and 28 may also (I) process mobilestation status data received from the cell site controllers; (ii) handleand switch calls between cells; (iii) process diagnostic information;and (iv) compile billing information. The transceiver of each cell site30 and 40 provides communications, such as voice and data, with mobilestation 38 while it is present in its geographic domain. The MTSOs 24and 28 may track and switch mobile station 38 from cell site to cellsite, as the mobile station passes through various coverage areas. Whenmobile station 38 passes from one cell to another cell, the MTSO of thecorresponding cell may perform a "hand-off" that allows the mobilestation to be continuously serviced.

In the current North American cellular system, any given market area maybe serviced by up to two competing service providers of cellular airtime communication services (wireless carriers). By FederalCommunications Commission (FCC) regulations, the two competing wirelesscarriers are assigned different groups of frequencies through whichservices are provided. A frequency set typically includes controlchannels and voice channels. The control channels are used forpreliminary communications between a mobile station and a cell site forsetting up a call, after which a voice channel is assigned for themobile station's use on that call. The assigned frequency sets aregenerally referred to as "A band frequencies" and "B band frequencies".Typically, the A band frequencies are reserved for non-wireline serviceproviders, while the B band frequencies are reserved for the incumbentwireline service providers. While each frequency set for a givencellular service market area is assigned to only one service provider,in different market areas the same frequency set may be assigned todifferent service providers or companies.

Depending upon which wireless carrier the user of the mobile stationsubscribes to, the home frequency set of the user may correspond to theA frequency band or the B frequency band. Whenever a call is placed bythe mobile station, the unit will ordinarily attempt to use the homefrequency set to establish the call. If a call is handled outside of theuser's home market area, then the unit is said to be "roaming" andservice will be attempted through a frequency set of a non-home serviceprovider. Typically, the user's home service provider will have aroaming agreement or reciprocal billing arrangement with the non-homeservice provider to permit service to be extended to the user's mobileunit when it is roaming in the non-home service provider's market area.

Whereas cellular typically operates in the 800-900 MHZ range, PCS isexpected to operate in the 1.5 to 1.8 GHz range. In North America, theFCC has awarded PCS licenses in six additional bands (i.e., the A-Fcarrier blocks or bands). PCS covers a broad range of individualizedtelecommunication services that let users communicate irrespective ofwhere they are located. With PCS, personalized numbers are assigned toindividuals rather than to the mobile stations, and call completion isperformed regardless of the location of the user. PCS may be implementedthrough conventional macro-cellular techniques or through PersonalCommunications Networks (PCN) that utilize light, inexpensive handheldhandsets and communicate via low-power antennas that are intended tooperate in a similar fashion to that of large scale cellular telephonenetworks, but operate within small geographic or microcellular areas. Itis anticipated that PCNs will operate within the same frequency band inmost countries (e.g., 1850-1990 MHZ), while cellular systems willoperate in different frequency bands in various countries.

The mobile station may include a memory device, such as a numberassignment module (NAM), in which an assigned phone number and a systemidentification code (SID) and/or System Operator Code (SOC) is stored touniquely identify the home service provider for the unit. In the NorthAmerican cellular system, each provider within a market area is assigneda distinct, fifteen bit SID. IS-136 service providers are also assigneda 12-bit SOC for use throughout all their market areas. In Europe, onthe other hand, the Global System for Mobile Communications (GSM)standard (see, for example, Recommendation GSM 02.11, ServiceAccessibility, European Telecommunications Standards Institute, 1992)defines a process for network selection based on the mobile stationreading the GSM equivalent of the SID, called the Public Land MobileNetwork (PLMN) identity.

The SID or equivalent system identification number is broadcast by eachwireless carrier and is used by the mobile station to determine whetheror not the mobile station is operating in its home network or if it isoperating in a roaming condition. The mobile station makes thisdetermination by reading the SID broadcast in the cellular market areawhere it is located, and comparing it to the home SID stored in the NAMof the cellular phone unit. If the SIDs do not match, then the mobilestation is roaming, and the mobile station must attempt to gain servicethrough a non-home service provider. Due to the imposition of a fixedsurcharge or higher per unit rate, the airtime charges when the mobilestation is roaming are customarily higher than when it is operatingwithin its home network.

Operation under a roaming condition is often under the control of themobile station user. The user can select whether the mobile station willoperate in a Home System Only, A Band Only, B Band Only, A BandPreferred, or B Band Preferred operating mode. The user typicallycontrols the system preference and mode operation through menu choice orselection. This current method of roaming control is conventionallyknown as "Preferred System Selection". In the most common roamingsituation, the mobile station remains on the same band as the homecellular network. That is, if the mobile station is homed to a cellularnetwork with an odd numbered SID (which is normally assigned to an Aband cellular service provider), then the mobile station will obtainservice from the A band cellular service provider when roaming.

Occasionally, the home service provider will program a mobile stationwith negative SIDs. Negative SIDs correspond to SIDs on which the mobilestation should not obtain service. Negative SIDs may be used, forexample, if roaming agreements are not in place between differentcellular service providers. An example of a mobile station that utilizesnegative SIDs is disclosed in BLAIR, U.S. Pat. No. 4,916,728. As analternative to negative SIDs, some mobile stations are programmed withpositive or preferred SIDs. Positive or preferred SIDs are SIDs on whichthe mobile station should attempt to obtain service when selecting acellular carrier frequency. An example of a mobile station that utilizespreferred SIDs is disclosed in BARBER et al., U.S. Pat. No. 5,442,806.The use of preferred SIDs facilitate the selection of a preferredservice provider when the mobile station is roaming.

With the maturation of mobile communication, a variety of advancedservices or service offerings have become available to mobile stationusers. For example, mobile station users may now elect to subscribe tomessaging services (such as voice mail, text messaging or Short MessageService (SMS)), or other services such as call waiting indication, voiceprivacy, etc. SMS and other forms of teleservices may be provided to amobile station via a message center connected to the cellular network.However, when roaming in another market area, certain wireless carriersin that market may not support all of the advanced services to which theuser subscribes. Consequently, when roaming, the user may lose use ofsome or all of the advanced services that the user is accustomed tousing.

Moreover, some large companies have come to depend upon the use ofmobile stations and wireless communications. As a result of the largevolume of such usage, they have set up corporate accounts with wirelesscarriers. These accounts are referred to by the wireless carriers asNational Accounts. Preferred roaming rates may be negotiated for aNational Account with particular wireless carriers in certain geographicmarket areas. Thus, when a mobile station roams to one of these marketareas, the National Account subscriber may prefer a different wirelesscarrier from the carrier preferred by the mass market. Furthermnore, acorporation may require its personnel to subscribe to particularadvanced services, e.g., a messaging service so the personnel is alwaysreachable. Conventional mobile station equipment and systems do notpermit a corporation to control which carrier roaming personnel will usein order to obtain beneficial rates and to receive selected requiredadvanced services.

Thus, there is a need in the cellular and mobile network industries toprovide some form of intelligent or automatic roaming in which themobile station obtains service on the cellular network with which thehome cellular service provider has the best roaming agreement (or thecellular service provider's own network in the roaming area, if it isnot in the same band as the home system), and/or which supports theservices the user requires. Two factors have primarily led to this need.First, large cellular service providers rarely operate in the same bandin all markets. Second, cellular service providers have chosen to offerdifferent advanced technologies or services. Consequently, the mobilestation may have to change bands to obtain the required services.

Further, there is a need to provide intelligent roaming capabilities fora mobile station which will not require any changes to present networkinterface standards (e.g. IS-41) or air interface standards (e.g.,IS-136, IS-91A, IS-95). Such features are desirable in order to pen-nitnew intelligent roaming capabilities to be readily utilized by a mobilestation and to allow seamless integration of such capabilities withoutmodification to present industry standards. For more information onnetwork interface standards such as Interim Standard 41 (IS-41), see,for example, TIA/EIA-IS-41.5-C, Cellular RadiotelecommunicationsIntersystem Operations: Signaling Protocols, Telecommunications IndustryAssociation, February 1996. For more information on air-interfacestandards such as Interim Standards 95 and 136 (IS-95 and IS-136), see,for example, TIA/EIA-IS-95-A, Mobile Station-Base Station CompatibilityStandard for Dual-Mode Wideband Spread Spectrum Cellular Systems,Telecommunications Industry Association, May 1995; TIA/EIA-IS-136.1-A,TDMA Cellular/PCS-Radio Interface-Mobile Station-Base StationCompatibility-Digital Control Channel, Telecommunications IndustryAssociation, October 1996; TIA/EIA-IS-136.2-A, TDMA Cellular/PCS-RadioInterface-Mobile Station-Base Station Compatibility-Traffic Channels andFSK Control Channel, Telecommunications Industry Association, October1996; and TIA/EIA/IS-136.1-A-1, Addendum No. 1 to TIA/EIA/IS-136.1-A,Telecommunications Industry Association, November 1996.

Another desirable feature is to provide over-the-air programming of amobile station to permit reprogramming of the mobile station with newintelligent roaming information as it becomes available. Such a featurewould permit the "intelligence" that is incorporated into the mobilestation to be updated and stored with ease, without requiring the userto bring the mobile station to a technician or operator forreprogramming.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, an apparatus isprovided for providing preferred wireless carrier information for use bya mobile station when the mobile station is roaming outside of a homemarket area. The invention provides intelligent roaming capabilitiesacross single and multiple hyperbands. The apparatus comprises adatabase, a generator, and a data-providing device. The database storespreferred wireless carrier identities for a plurality of market areasbased upon predetermined classes of service. The generator generates alist of the preferred wireless carrier identities based upon a selectedclass of service and the home market area of the mobile station. Thedata-providing device provides the generated list to the mobile stationdesignated with the selected class of service.

Preferably, the database further comprises a plurality of predeterminedhome market areas, and the generated list of preferred wireless carrieridentities is based upon the selected class of service and a selectedone of the plurality of home market areas. Moreover, the data-providingdevice provides the generated list to the mobile station designated withthe selected class of service and the selected home market area.

In another embodiment the database further comprises a plurality ofnational accounts, and the generated list of preferred wireless carrieridentities is based upon the selected class of service and a selectednational account. In this embodiment, the data-providing device providesthe generated list to each mobile station designated with the selectedclass of service and the selected national account.

According to another embodiment the list includes a backup carrieridentity for use in the event service from the preferred wirelesscarrier is not available. Moreover, the data-providing device providesthe list of preferred wireless carrier identities to the mobile stationsvia wireless communication.

According to another aspect of the present invention, the generatorgenerates the list of preferred wireless carrier identities based uponthe plurality of wireless carriers' roaming airtime rates, services orair interface technology provided for each of the plurality of marketareas. The generator may then update the list of preferred wirelesscarrier identities when one of the plurality of wireless carrierschanges a communication characteristic (such as roaming airtime ratesthe wireless carrier charges for a market areas, and services thewireless carrier offers to market areas) for one of the plurality ofmarket areas. The data-providing device provides the updated list ofpreferred wireless carrier identities to all mobile stations previouslyprovided with the list the generator updated.

Preferably each mobile station is assigned to one of the predeterminedclasses of service based upon services to which the mobile station usersubscribes. The list of preferred wireless carrier identities comprisesa plurality of entries indicating a system identification number (and/orSystem Operator Code) and a corresponding frequency band for eachpreferred wireless carrier.

According to another embodiment of the present invention, a mobilestation is provided that comprises a memory and a selector. The memorystores a list of preferred wireless carrier identities based upon aselected class of service for a plurality of market areas. The selectorautomatically selects a preferred wireless carrier from the list storedin the memory when the mobile station is roaming and enters one of themarket areas of the plurality of market areas. Preferably, the mobilestation switches to the preferred wireless carrier, selected from thelist of preferred wireless carrier identities, to use for communicationin response to the mobile station roaming to the predetermined marketarea. The list of preferred wireless carrier identities may bedownloaded to the memory from a message center via a communications linkestablished between the message center and the memory. Thecommunications link may comprise a wireless communications link and/or ahard-wire or wired communications link. Programming of the mobilestation unit and entry of preferred wireless carrier identities may alsobe performed manually by using the keypad of the mobile station unit.

According to another embodiment of the present invention, a system isprovided for selecting preferred wireless carriers from a plurality ofwireless carriers for use by a mobile station when the mobile station isroaming outside of a home market area. The system comprises a database,a generator, a data-providing device, a memory and a selector. Thedatabase stores preferred wireless carrier identities for a plurality ofmarket areas based upon predetermined classes of service. The generatorgenerates a list of the preferred wireless carrier identities based upona selected class of service and the home market area of the mobilestation. The data-providing device provides the generated list to eachmobile station designated with the selected class of service. Thememory, provided within the mobile station, stores the generated list ofpreferred wireless carrier identities. The selector selects a preferredwireless carrier from the list stored in the memory when the mobilestation enters one of the market areas of the plurality of market areas.Thus, the mobile station switches to the preferred wireless carrier,selected from the list of preferred wireless carrier identities, forcommunication in response to the mobile station roaming to thepredetermined market area.

Preferably, the database further comprises a plurality of predeterminedhome market areas and national accounts. Thus, the generated list ofpreferred wireless carrier identities is based upon the selected classof service, a selected national account, and a selected one of theplurality of home market areas.

According to another embodiment of the present invention, a method isprovided for selecting a preferred wireless carrier for a mobile stationto enable wireless communication when the mobile station is roamingoutside of a home market area. A database of preferred wireless carrieridentities for a plurality of market areas based upon predeterminedclasses of service is compiled at a predetermined location remote fromthe mobile station, and a list of preferred wireless carrier identitiesis generated based upon a selected class of service and the plurality ofmarket areas. The list is provided to a storage device associated withthe mobile station designated with the selected class of service toenable a selection of the preferred wireless carrier. The methodcomprises receiving a signal transmitted by a wireless carriercontaining the wireless carrier's identity, comparing the wirelesscarrier's identity to the database of preferred wireless carrieridentities stored in the mobile station, and switching a communicationsmode within the mobile station so as to obtain service from the highestpriority wireless carrier available.

According to another embodiment of the present invention, an apparatusis provided for selecting preferred wireless carriers from a pluralityof wireless carriers for use by a mobile station when the mobile stationis roaming outside of a home market area. The apparatus comprises adatabase, a generator, a data-providing device, a mobile station, amemory, and a selector. The database stores preferred wireless carrieridentities for a plurality of market areas based upon predeterminedclasses of service, predetermined national accounts and predeterminedhome market areas. The generator generates a list of the preferredwireless carrier identities based upon a selected class of service, aselected national account, a selected home market area and the pluralityof market areas. The data-providing device provides the generated listto mobile stations designated with the selected class of service,selected national account and selected home market area. The mobilestation is useable in a roaming environment. The memory is associatedwith the mobile station and stores the generated list of preferredwireless carrier identities. The selector selects a preferred wirelesscarrier from the list stored in the memory when the mobile stationenters a market area of the plurality of market areas. Preferably, thedata-providing device transmits the list of preferred wireless carrieridentities via over-the-air programming.

According to another embodiment of the present invention, a method isprovided for downloading a list of wireless carrier identities stored ina database to a mobile station's memory. The database contains the listof wireless carrier identities from which the mobile station selects apreferred wireless carrier when the mobile station is roaming outside ofa home market area to use for wireless communication. The database has aplurality of national account fields, a plurality of home market areafields, and a plurality of class of service fields. Each mobile stationis assigned to a national account, a home market area and a class ofservice. The database determines the list of preferred wireless carrieridentities for each class of service field, within each national accountfield within each market area field. Memory is provided within themobile station for storing the list of wireless carrier identities andpreferred wireless carrier identities corresponding to the mobilestation's wireless carrier identities and national account, class ofservice and home market area. The method comprises determining when thelist of wireless carrier identities stored in the mobile station'smemory is outdated. When the list is outdated: determining if the mobilestation is registered with its home location register; locating themobile station and downloading an updated list of carrier identities tothe mobile station when it is determined the mobile station isregistered with the home location register; notifying a message centerwhen the mobile station registers and then downloading a new list ofpreferred carrier identities to the mobile station when it is determinedthe mobile station is not registered with the home location register(e.g., when delivery is pending). Preferably, the downloading furthercomprises a throttling scheme which controls the number of mobilestations to which the downloading occurs during a predetermined periodof time.

DESCRIPTION OF THE DRAWINGS

The present invention is further described in the detailed descriptionwhich follows, by reference to the noted plurality of drawings by way ofnon-limiting examples of preferred embodiments of the present invention,in which like reference numerals represent similar parts throughout theseveral views of the drawings, and wherein:

FIG. 1 illustrates the basic components of a conventional cellularnetwork system;

FIG. 2A illustrates exemplary components of a cellular or PCS networksystem implemented according to aspects of the present invention;

FIG. 2B illustrates, in accordance with an aspect of the presentinvention, an exemplary mobile station implemented as a wireless phoneunit;

FIG. 2C is a general block diagram of the components of the mobilestation of FIG. 2B, in accordance with an aspect of the presentinvention;

FIG. 3 is a flow diagram of the processes and operations of anintelligent roaming process, according to an embodiment of theinvention;

FIG. 4 is a diagram of an exemplary architecture that may be used todownload the PSL/IRDB to a mobile station, according to an embodiment ofthe present invention;

FIG. 5 illustrates an exemplary message flow for performing over-the-airprogramming of a mobile station, according to an embodiment of thepresent invention;

FIG. 6 illustrates, in accordance with another embodiment of the presentinvention, an exemplary message flow for performing over-the-airprogramming of a mobile station; and

FIG. 7 is a general block diagram of an exemplary network architecturefor implementing and administering the intelligent roaming capabilitiesof the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the accompanying drawings, a detailed description of thepreferred embodiments and features of the present invention will beprovided.

The present invention relates to a mobile station with intelligentroaming and/or over-the-air programming features. The present inventionpermits a mobile station to immediately obtain service on a preferredcellular, PCS or other wireless network system meeting a subscriber'sservice requirements. The selection or designation of such a systemcarrier may be configured to comply with, for example, preferences of acorporation having a National Account with the home wireless carrier,when there are multiple bands available.

According to an aspect of the present invention, a Preferred SystemIdentification List (PSL) (for cellular systems) and/or an IntelligentRoaming Database Downloading (IRDB) (for cellular, PCS and otherwireless systems) is stored within a memory or storage device of themobile station. When the mobile station is roaming, the PSL or IRDB isaccessed to indicate the band where the mobile station will find apreferred system. If the mobile station is capable of operating ineither a cellular or PCS system, the mobile station may access the PSLor IRDB depending on the type of system that it is located in or itscurrent operating mode. The present invention, however, is not limitedto cellular or PCS networks, and may be used with other wirelessnetworks and environments, such as Wireless Communication Services(WCS), Enhanced Specialized Mobile Radio (ESMR), iDENS, and reproposedchannels 60-69. The invention, therefore, may provide intelligentroaming capabilities across single and multiple hyperbands and is notlimited to cellular and PCS systems. Further, the preferred system willbe a system which supports the service requirements of a particularsubscriber. The preferred system may also satisfy the preferences of aparticular National Account reflecting preferred rates negotiated forthat National Account in the market area that the mobile station isroaming in. Further, it is possible that the preferred system be definedand/or selected according to a required or preferred air-interfacetechnology (e.g., TDMA, CDMA, PACS, GSM and PCS-1900) to be utilized bythe mobile station.

In addition, according to another aspect of the present invention,programming of the PSL/IRDB in the mobile station may be performedover-the-air (i.e., by wireless communication) to permit easyreprogramming of the mobile station with new preferred systeminformation as it becomes available.

FIGS. 2A-2C illustrate an exemplary network architecture and exemplarysystem components for implementing the intelligent roaming capabilitiesof the present invention. In FIGS. 2A-2C, a mobile station-basedapproach is provided for implementing the intelligent roamingcapabilities of the invention. According to the mobile station-basedapproach of the invention, each mobile station is programmed withintelligent roaming capabilities so that it can determine which systemit should obtain service on prior to registration. As will beappreciated from the following description, the mobile station-basedapproach for providing intelligent roaming capabilities has severaladvantages, including the ability to integrate into conventionalcellular or PCS network environments without requiring modification tothe main network components, and without requiring any changes tocurrent network interface standards (e.g., IS-41) or air interfacestandards (e.g., IS-136, IS-91A, IS-95).

In FIG. 2A, exemplary components of a cellular network implemented withthe features of the present invention are illustrated. Although thepresent invention is described with reference to a cellular networkenvironment, the present invention may also be applied to other networkenvironments (e.g., PCS or PCN network environments), in which adifferent radio frequency, lower powered cell sites and smaller cellareas are utilized. In FIG. 2A, a mobile station 68 is provided with amemory device 67 for storing a Preferred System Identification List(PSL) and/or Intelligent Roaming Database (IRDB). According to an aspectof the present invention, the PSL/IRDB may be preprogrammed into themobile station prior to activation of the unit and/or may bereprogrammed and updated by using, for example, a physical interface(such as a computer interface) or over-the-air programming techniques,such as those discussed below. The PSL/IRDB indicates the band or bandswhere a mobile station may find a preferred system when roaming. Thatis, the PSL/IRDB may include the SID and/or SOC corresponding to thewireless carrier the mobile station should use for wirelesscommunication in order to obtain the services required by thesubscriber. Furthermore, the PSL/IRDB may include information on theband the mobile station should communicate over in accordance with theNational Account to which the subscriber is a member.

The mobile station 68 may comprise portable phone units, units installedin vehicles and fixed subscriber units. By way of non-limiting example,the mobile station 68 may be implemented as a cellular telephone unitwith a transceiver and antenna (see, for example, FIGS. 2B and 2C) tocommunicate by, for example, radio waves with one or more cell sites. InFIG. 2A, cell sites 75 and 95 are illustrated. The mobile station 68 mayplace or receive calls by communicating with cell site 75 or cell site95, depending upon the location of the mobile station and the cellcoverage area that is provided by each cell site. That is, when mobilestation 68 is located within cell coverage area 70 it may communicatewith cell site 75, and when it is located within cell coverage area 90it may communicate with cell site 95. As will be appreciated by thoseskilled in the art, the actual cell coverage area for a cell site willdepend upon various factors, including the power of the transceiver ofthe cell site, the placement and location of the cell site, and thetopography of the surrounding areas where the cell site is located.Further, although only two cell sites are depicted in FIG. 2A, thecellular network may of course include more than two cell sites.Moreover, it should be noted that the various components of the cellularnetwork depicted in FIG. 2A are provided for the purpose of illustrationonly, and that other types of network arrangements may of course beprovided to implement the features of the invention. In addition, morethan one cell site may be served by each MTSO.

Various air-interface technologies (e.g., TDMA, CDMA, PACS, GSM andPCS-1900) may be utilized to facilitate communication between the mobilestation and the cell sites. Each of the cell sites 75 and 95 mayinclude, for example, a radio transceiver (not shown) and may beconnected by landlines 32 or other communication links to MobileSwitching Centers (MSCs) or Mobile Telephone Switching Offices (MTSOs)54 and 58. Landlines 32 may also be utilized to connect the MTSOs 54 and58 to the Public Switched Telephone Network (PSTN) 82. The MTSOs 54 and58 may also be connected to a Short Message Service Center (SMSC) (notshown in the drawings) to facilitate the delivery of short messages tomobile station 68.

The MTSOs 54 and 58 may be conventional digital telephone exchanges thatcontrol the switching between the PSTN 82 and the cell sites 75 and 95to provide wireline-to-mobile, mobile-to-wireline and mobile-to-mobilecall connectivity. The MTSOs may provide various functions, including(i) processing mobile station status data received from the cell sitecontrollers, (ii) handling and switching calls, (iii) processingdiagnostic information, and (iv) compiling billing information. Thetransceiver (not shown) of each cell site 75 and 95 may providecommunication services, such as voice and data communication, withmobile station 68 while it is present in its cell coverage area.Tracking and switching of the mobile station from cell site to cell sitemay be handled by the MTSOs, as the mobile station passes throughvarious cell coverage areas. When, for example, mobile station 68 passesfrom one cell to another cell, the MTSO of the corresponding cell mayperform a "hand-off" that allows the mobile station to be continuouslyserviced if on a voice or data call.

As shown in FIG. 2B, the mobile station 68 may be implemented as acellular or wireless phone unit that comprises an antenna 62, a speaker64, a microphone 69, a display 65, and a keypad 66 for enteringalphanumeric information. The phone unit of mobile station 68 may beconstructed in a similar fashion to that of a conventional cellulartelephone, with the exception of unique programming and memoryconfigurations and contents for implementing the intelligent roamingaspects of the present invention. Further, the memory 67 of the mobilestation 68 may be configured to handle a greater capacity than that of aconventional cellular telephone, in order to accommodate the PSL/IRDBand other operational information of the present invention.

Accordingly, mobile station 68 may include a speaker 64 that comprises aconventional speaker for converting electrical audio signals received byantenna 62 into acoustic audio signals, and a microphone 69 thatcomprises a conventional microphone for converting voice utterances of auser from acoustic audio signals into electrical audio signals fortransmission by antenna 62. In addition, display 65 and keypad 66 may beimplemented by conventional display and keypad devices for displayingand permitting entry of alphanumeric and other information. By way of anon-limiting example, display 65 may comprise dedicated status lightsand/or a liquid crystal display (LCD) to indicate the status of thecellular telephone unit (e.g., "No Service", "Roam", etc.). Further,keypad 66 may comprise menu selection buttons and/or a conventionaltwelve button, alphanumeric keypad for initiating and receiving calls,and programming or selecting operating conditions for the mobilestation.

Memory 67 of the mobile station 68 may store the PSL/IRDB and otheroperational information of the present invention. Memory 67 may comprisea read-write memory device that has an independent power supply so thecontents will not be effected by power downs of ordinary duration. Byway of non-limiting examples, memory 67 may be implemented by aprogrammable Electronically Erasable Programmable Read Only Memory(EEPROM), a Complimentary Metal Oxide Semiconductor (CMOS) memory chip,or a conventional Random Access Memory (RAM) with an independent powersupply.

The handset storage capability provided by memory 67 may vary amongdifferent types or models of the mobile stations. Preferably, low tiermobile stations should be able to store a minimum of 30 preferred SIDsand high tier mobile stations should be capable of storing a minimum of100 preferred SIDs. Further, dual band handsets designed to supportcommercially available service carriers, typically can store up to 88SIDs and/or SOCs. To address the variability in PSL/IRDB storagecapability in mobile stations, the entries in the PSL/IRDB should beprioritized, and the mobile stations can truncate the PSL/IRDB once themaximum storage capacity is reached.

An exemplary block diagram representation of the components of themobile station 68 depicted in FIG. 2B is provided in FIG. 2C. Asdiscussed above, the cellular telephone unit of the mobile station 68may comprise an antenna 62, a speaker 64, a display 65, a keypad 66, anda microphone 69. The antenna 62 may be connected to a transceiver 63,which in turn is connected to a control system 61. Control system 61 maybe implemented as a microprocessor-based, control system and may beprogrammed to carry out the intelligent roaming features and logic ofthe present invention. The programming of control system 61 may becarried out by any suitable combination or use of software, hardwareand/or firmware. Control system 61 may control the various components ofthe mobile station 68 to permit a user to send and receive calls andprogram the mobile station. In addition, control system 61 may haveaccess to memory 67, in which the PSL/IRDB and other programminginformation is stored, for directing operation of the mobile station. Amore detailed description of the various processes and functions of theintelligent roaming features of the present invention, as well as thelogic steps associated with the intelligent roaming method, is providedbelow with reference to the accompanying drawings.

Referring now to FIG. 3, an exemplary logic flow diagram of theintelligent roaming process or method of the present invention will bediscussed, in accordance with an embodiment of the present invention.The various processes and operations illustrated in FIG. 3 may becarried out by control system 61 of the mobile station 68 through theuse of programmed logic or firmware. The intelligent roaming process ofthe present invention permits each mobile station to automaticallyobtain service from the most appropriate and/or preferred wirelesscarrier. Although the description below is made with reference to acellular network environment, the various processes and operation mayalso be applied to PCS or PCN network systems.

In FIG. 3, a mobile station enters an initialization state at step S.2,when the mobile station is powered ON, changes systems, is in a "NoService" condition, or when an Intelligent Roaming mode (IR Mode) hasbeen selected by the user. After the mobile station has beeninitialized, the mobile station first scans for its home band (i.e., theset of frequencies corresponding to its home network system) at step S.4to locate a control channel. The set of frequencies corresponding to thehome band of the mobile station may be programmed into the mobilestation's memory (e.g., memory 67) by the home system service provider.

At step S.6, the mobile station determines whether it is in its homesystem or market area. Whether or not the mobile station is located inits home market area may be determined by analyzing the SID, SOC orequivalent system identification number of the cellular service providerfor the area in which the mobile station is located. By comparing theSID or SOC received on the control channel with the home SID or SOC ofthe home service provider, the mobile station may determine whether itis located in its home system. As described above, the home SID or SOCmay be stored in the NAM of the mobile station, or may be stored inanother appropriate memory or storage device of the mobile station. Forexample, the home SID or SOC may be stored separately from the PSL/IRDBof the mobile station, or may be stored in memory 67 as part of thePSL/IRDB.

If the mobile station determines that it is located in its home marketarea, then at step S.8, the mobile station will stay on that band andobtain service from the home wireless carrier/cellular service provider.However, if the mobile station determines that it is not in its homemarket area, then at step S.10 the PSL/IRDB stored in the mobile stationwill be accessed and searched at step S.12 to determine if the receivedSID or SOC corresponds to the preferred wireless carrier for the currentmarket area. If the received SID or SOC corresponds to the SID or SOC ofthe preferred wireless carrier, at S.14 the mobile station 68 obtainsservice from the current wireless carrier transmitting the received SIDor SOC. However, if at S.12 the mobile station 68 determines the currentSID or SOC is not the preferred SID or SOC, the mobile station obtainsservice from the band indicated in the PSL/IRDB at step S.16.

In accordance with an aspect of the present invention, the PSL/IRDBstored in the mobile station may comprise a table of entries includingthe SIDs and/or SOCs and corresponding frequency band(s) of thepreferred service providers for each market area. The preferred serviceproviders may correspond to cellular service providers the mobilestation's home system has a reciprocal agreement or billing arrangementwith to provide service when the mobile station is roaming. In addition,the preferred system may also be defined and/or selected according to apreferred or required air interface technology. Entries in the PSL/IRDBmay be the SIDs or SOCs associated with each region within which one ormore preferred service providers exist (e.g., the PSL/IRDB may includeentries for one or more of the SIDs and/or SOCs assigned in the NorthAmerican cellular system). If more than one preferred or target systemexists for a given region, then the preferred systems in an PSL/IRDBentry may be listed in order of preference and/or the air interfacetechnology may be provided for each preferred system so that the mobilestation may select the most appropriate system for that region. Anexample of the information fields or elements for the PSL/IRDB andPSL/IRDB entries is provided below in Table 1. In the PSL/IRDB, there isone carrier per market area. However, in the case where the carriercovers only part of the market area, a second carrier may also beprovided. For example, PCS Service Provider A covers only part of theWashington, D.C. market area. If the preferred carrier in Washington,D.C. is PCS Service Provider A and the mobile station 68 is outside ofthe PSC Service Provider A's coverage, the mobile station mustcommunicate via a different carrier and, therefore, the second carrierfor that market area (Washington, D.C.) from the PSL/IRDB is used.

                  TABLE 1                                                         ______________________________________                                        PSL/IRDB Entries                                                              Market Area                                                                            SID and/or SOC       Frequency                                       ______________________________________                                        Market Area 1                                                                          Preferred SID/SOC for Market Area 1                                                                Corresponding                                            (and Alternative SID/SOC if required)                                                              Band                                            Market Area 2                                                                          Preferred SID/SOC for Market Area 2                                                                Corresponding                                            (and Alternative SID/SOC if required)                                                              Band                                            . . .    . . .                . . .                                           Market Area N                                                                          Preferred SID/SOC for Market Area N                                                                Corresponding                                            (and Alternative SID/SOC if required)                                                              Band                                            ______________________________________                                    

In Table 1, N represents the total number of market areas within thecountry/geographic area the cellular/PCS system covers.

Because some markets operate using multiple SIDs, PSLs/IRDBs will needto be administered on a per SID basis. Even within a given market (SID),different PSLs/IRDBs will be required to support different classes ofservice. This can be demonstrated by an example of two cellularsubscribers who roam into a geographic area (e.g., Austin) from the samemarket (e.g., Dallas). If one subscriber desires to receive ShortMessage Service, they may roam to a service provider supporting thatservice (e.g., Service Provider A) while the other subscriber whorequires only voice (a class of service hereinafter referred to aswireless POTS (Plain Old Telephone Service)) may roam to another serviceprovider providing a more attractive roaming rate (e.g., ServiceProvider B). This is required because not all service providers willsupport all classes of service. The roaming paradigm must change toaccommodate scenarios like these.

Table 2 lists exemplary wireless features of the mobile stations andidentifies them with classes of service, based on the requirements toprovide these features.

                  TABLE 2                                                         ______________________________________                                        Classes of Service For Wireless Features                                                 Requirements to Provide                                                                         Resulting Class of                               Wireless Feature                                                                         Feature           Service                                          ______________________________________                                        Wireless Plain Old                                                                       Roaming Agreement (RA)                                                                          Class of Service 1                               Telephone Service                                                             (POTS)                                                                        Analog Circuit-                                                                          RA                Class of Service 1                               Switched Data                                                                 Private Systems                                                                          RA, Digital Control Channel                                                                     Class of Service 2                               (PSIDs)    (DCCH)                                                             Short Message                                                                            RA, DCCH          Class of Service 2                               Service (SMS)                                                                 Message Waiting                                                                          RA, DCCH          Class of Service 2                               Indicator (MWI)                                                               Extended Battery                                                                         RA, DCCH          Class of Service 2                               Life                                                                          TDMA Packet Data                                                                         RA, DCCH +, DTC + (where +                                                                      Class of Service 3                                          indicates that the channel                                                    requires enhanced capabilities                                                to support this service)                                           Voice Privacy                                                                            RA, DCCH, Digital Traffic                                                                       Class of Service 3                                          Channel (DTC)                                                      Digital Circuit-                                                                         RA, DCCH, DTC     Class of Service 3                               Switched Data                                                                 ______________________________________                                    

National Accounts may require different PSLs/IRDBs than the more generalmass market. For instance, preferred roaming rates may be negotiated fora National Account in one geographic location which would cause theNational Account subscriber to prefer a service provider different fromthe service provider preferred by the mass market subscribers.

An exemplary National Accounts database according to a preferredembodiment of the present invention is illustrated below in Table 3.Without any loss in generality, Table 3 shows PSLS instead of IRDBs.Because a wireless carrier in different home market areas typically hasdifferent roaming partners, each home market's PSL/IRDB may bedifferent. Consequently, the parameters and information fields in Table1 should be replicated for each home market area. Thus, for each homemarket area, a PSL/IRDB is generated depending on the National AccountGroup a subscriber is a member of and the class of service required bythe subscriber. In Table 3, there are n classes of service (COS) and mNational Accounts (NA). NA₀ represents the mass market account. Thedatabase of Table 3 may be stored within a switch or computer in thecentral office (message center). Although one such database should beprovided for each home market area, one database could serve multiplemarkets. In Table 3, a National Account database is illustrated for homemarket area 1. This database may serve or be used for other home marketareas (e.g., home market areas 2 through p, where p is the total numberof home market areas), or separate databases may be provided for eachhome market area that exists.

                  TABLE 3                                                         ______________________________________                                        Database Representation                                                       Home Market Area 1                                                                           COS.sub.1                                                                             COS.sub.2 . . .                                                                             COS.sub.n                                ______________________________________                                        NA.sub.0       PSL.sub.01                                                                            PSL.sub.02    PSL.sub.0n                               NA.sub.1       PSL.sub.11                                                                            PLS.sub.12    PSL.sub.1n                               . . .          . . .   . . .         . . .                                    NA.sub.m       PSL.sub.m1                                                                            PSL.sub.m2    PSL.sub.mn                               ______________________________________                                    

The size and configuration of the National Accounts database may beconfigured according to system preferences and/or requirements. Table 4below indicates an exemplary configuration for the databases, indicatingthe number of databases and the size of each field for each database.

                  TABLE 4                                                         ______________________________________                                        Database Sizing                                                               Entry       Size          Comment                                             ______________________________________                                        Number of Home                                                                             32                                                               Market Area databases                                                         Classes of Service                                                                         16           Some reserved for future                                                      use, e.g., PCS-1900,                                                          CDMA                                                National Accounts                                                                         512                                                               Preferred SIDs                                                                            100 max. per COS/NA                                                           per Home Market Area                                              Alpha Tags  3 per Home SID                                                                              For Home SID Alpha                                                            Tag, Preferred SID                                                            Alpha Tag, Neutral                                                            SID Alpha Tag                                       ______________________________________                                    

In Table 4, alpha tags relate alpha numeric system identities that aretypically displayed on the mobile station's display screen uponregistration with the system. The alpha tages may be stored in thememory or the PSL/IRDB of the mobile station.

The PSL/IRDBs are generated for each National Account upon theestablishment of a National Account. A representative of the companycreating the National Account typically selects the preferred carrierfor each market area depending on the airtime rates and the class ofservice required. For example, the wireless carrier with the mostfavorable airtime rates is typically selected for each market area.However, if it is determined to be imperative to maintain a class ofservice, the mobile station will switch to the wireless carriersupporting the required class of service, even if a less favorable rateresults.

Several events may cause the PSL/IRDB to become outdated. For example,the PSL/IRDB may change whenever the mobile station changes its class ofservice. Also if the home market service provider establishes a newroaming agreement with a carrier, the rates may change and newPSLs/IRDBs must be generated. Another time the PSL/IRDB may change iswhen a carrier adds a new technology or class of service. Once thePSLs/IRDBs become outdated, a new list should be downloaded to allmobile stations 68 affected by the update. Such downloading may becarried out by utilizing over-the-air programming (OAP) techniques, suchas those discussed below.

Typically, when the mobile station is initially activated, the mobilestation 68 is programmed with the PSL/IRDB by an interface thatphysically connects to the mobile station. The PSL/IRDB for eachparticular mobile station is selected according to the mobile station'shome market area, National Account and class of service. Thesedesignators are assigned to each mobile station upon initial activation.However, the database may be downloaded by an interface that usesover-the-air programming (OAP) and downloading. Further, programming ofthe mobile station 68 may be performed manually through use of thekeypad of the mobile station.

In order to provide increased flexibility, such programming anddownloading of PSL/IRDB information may be performed over-the-air. Inaccordance with an aspect of the present invention, over-the-airprogramming of the PSL/IRDB allows the PSL/IRDB to be initiallydownloaded and/or updated to the mobile station without requiring theuser to bring the mobile station into a service center. The over-the-airprogramming capability of the present invention provides severaladvantages, including improving the ease by which the mobile station canbe programmed with new preferred system information as it becomesavailable to the home cellular or PCS operator.

FIG. 4 illustrates a top level architecture or arrangement for thePSL/IRDB downloading using Over-the-Air Activation (OAA) andOver-the-Air Programming (OAP). As shown in FIG. 4, an applicationreferred to as an Over-the-Air Activation Function (OTAF) 100 is storedat an external platform. The OTAF 100 may be implemented with softwareor programmed logic, and be adapted to perform the various functionsdescribed herein. The OTAF 100 may be provided together with a databaseincluding the tables and entries described above with reference toTables 3 and 4. The platform at which the OTAF 100 and database areprovided may be a special purpose platform or may be incorporated intoan existing platform, such as a Short Message Service Center (messagecenter), a local switch, a Home Location Register (HLR), or a ServiceControl Point (SCP) of an Advanced Intelligent Network (AIN). In orderto perform administrative functions on the database of the OTAF 100,including populating and/or modifying PSL/IRDB entries in the database,a database administration access mechanism 101 may be provided. Thedatabase administration access mechanism 101 may be provided locally orremotely from the OTAF 100 and may be controlled and operated by a humanoperator. For example, the database administration mechanism 101 mayinclude an operator terminal provided at the Message Center (MC) or atthe Customer Service Center (CSC). In addition, the databaseadministration access mechanism 101 may include any known type of inputsource. Exemplary access schemes into the OTAF 100 include: (1) an OTAFplatform administrative terminal, (2) a TCP/IP feed directly from theCustomer Service Center (CSC), and (3) a dial-up modem connection from aremote facility. Preferably, the information is input via the ShortMessage Peer-to-Peer (SMPP) protocol which runs over TCP/IP.

In accordance with an aspect of the invention, the database of the OTAF100 may also maintain a subscriber database of all active mobilestations that are capable of receiving a new roaming database or tableentries. The subscriber database may be generated by the CustomerService Center (CSC) 102 and provided as input to the OTAF 100. When acustomer activates (or reactivates) a mobile station 68, the CSC 102enters a subscriber profile into the subscriber database. The profilepreferably includes routing identification information, such as MobileIdentification Number (MIN), Electronic Serial Number (ESN) and PrivateSystem IDs (PSIDs) for downloading into the mobile station 68. At thistime, the subscriber is preferably assigned a class of service (COS)designator and a home SID which are also entered into the subscriberdatabase. From this subscriber database, the OTAF 100 is able togenerate and send out the new or updated roaming database to each mobilestation on record. For this purpose, the OTAF 100 may include agenerator that generates a list of preferred wireless carrier identitiesfor the mobile station by comparing the entries and information in thedatabase with the profile criteria of the mobile station, including theselected COS, National Account and/or the home market area of the mobilestation. In addition, a preferred air-interface technology may bedefined for the mobile station by the CSC 102 and provided as input tothe OTAF 100 as additional criteria for generating a list of preferredcarrier identities for the mobile station. The appropriate PSL/IRDBentries are then forwarded to the mobile station by the OTAF 100.

More particularly, according to an aspect of the invention, the PSL/IRDBentries may be generated and downloaded to each mobile station inaccordance with the following procedure.

When a subscriber calls the Customer Service Center (CSC) 102 toactivate a mobile station handset 68, the CSC 102 representative assignsa MIN for the handset, identifies the features to which the subscriberis allowed, and determines the National Account status (either massmarket (NA₀) or a particular National Account). The CSC 102automatically identifies the Home SID based on the MIN, and the Class ofService based on the subscriber's features. The CSC 102 then sends theMIN, ESN, Home SID, COS, and National Account (NA) to the OTAF 100. TheCSC 102 may also determine and send the preferred air-interfacetechnology to be utilized by the mobile station as additional profilecriteria to the OTAF 100, as noted above. The OTAF 100 matches the Homemarket area or SID, COS, and/or NA with a PSL/IRDB entry in thedatabase, to generate a list of preferred wireless carrier identitiesfor the mobile station. If provided by the CSC 102, other criteria mayalso be utilized to select preferred carriers, such as the air-interfacetechnology defined for the mobile station. After generating the list ofpreferred wireless carrier identities, the OTAF 100 then proceeds toprogram the handset using, for example, the defined IS-136A message set.

In the reprogramming scenario, the PSL/IRDB will be downloaded withother OTAF information similar to that for new activations. In otherwords, upon reprogramming, if the National Account (NA), COS, MIN and/orany other parameters change, each changed parameter is reprogrammed ordownloaded into the mobile station 68 along with the new PSL/IRDB. Ifnone of the parameters have changed, only the updated PSL/IRDB isdownloaded to the mobile station 68.

When a PSL/IRDB needs to be updated, personnel may enter the new (ormodified) roaming PSL/IRDB into the OTAF 100 via, for example, anexternal terminal entry or the database administration mechanism 101. Awireless carrier's personnel will then set a flag in the OTAF 100indicating that a new PSL/IRDB for a particular COS/NA has been enteredand needs to be sent to mobile stations designated with that COS/NA.

The OTAF 100 then queries the subscriber's Home Location Register (HLR)104 via, for example, one or more Signaling Transfer Points (STP) 110 toidentify and determine the subscriber's mobile station 68 status andlocation. A throttling scheme is active at this point to limit thenumbers of queries sent to each HLR 104 in order to prevent overload.For example, a craft settable throttling mechanism may be utilized inorder to prevent flooding of the Home Location Register (HLR) 104 withSMSREQ messages or any other known message protocol for communicationwith an HLR. The message center (MC) or platform supporting the OTAF 100preferably has an internal teleservices ID prioritization scheme whichpushes messages to the top of the queue based on the teleservices ID.For instance, if multiple messages are being stored for a singlesubscriber, it may be desired to ensure that the mobile station has thelatest roaming database installed before a Cellular MessagingTeleservice (CMT) message is sent. OAA, OAP and CMT are identified bydifferent teleservice IDs.

If the mobile station 68 is available, the HLR 104 will return locationinformation (with, for example, a SMSNOT message) to the OTAF 100 (byway of, for example, one or more STPs 110) to permit routing of thePSL/IRDB entry information to the mobile station 68 via the servingMobile Switching Center (MSC) and the wireless network infrastructure.As illustrated in FIG. 4, the wireless network infrastructure forcommunicating with the mobile station 68 may include one or more MobileSwitching Centers (MSC) 106 and Base Stations (BS) 108. Once thelocation of the mobile station 68 is determined from the HLR 104 (and/orVisiting Location Register (VLR)--not illustrated in FIG. 4), the OTAF100 will route (via the appropriate STP 110) the database information topermit the serving MSC 106 and BS 108 to relay the PSL/IRDB entryinformation to the mobile station 68 by wireless communication,including transmission over-the-air. The wireless communication betweenthe BS 108 and the mobile station 68 may preferably use the IS-136standard, although any known standard may be used. Communication betweeneach MSC 106 and BS 108 may use conventional wired or wirelesscommunication links.

If the mobile station 68 is unavailable, the HLR 104 will set aninternal flag to notify the OTAF 100 when the handset or mobile stationbecomes active and/or registers. When the OTAF 100 receives locationinformation on the mobile station 68, the OTAF 100 sends the new roamingPSL/IRDB to the mobile station 68, as described above. Thereafter,normal OAA and/or OAP logic flow or processing may be carried outaccording to industry or forum defined standards and protocols (such asthe standards and protocols set for IS-136 by the Universal WirelessCommunications Committee (UWCC) or an open industry forum/group).

As described above, a throttling scheme may be used to preventoverloading of the network. For example, if a new roaming agreement isreached with another wireless carrier, many handsets will be effected.Consequently, the downloading of the new databases to all of the mobilestations will overload the network. Therefore, a craft-settablethrottling mechanism, i.e., to identify the number of maximum databasesto update at a time, is provided. Furthermore, the throttling mechanismmay allow favoring of one National Account over another when updatingthe databases, i.e., downloading the new data to subscribers of oneNational Account before downloading data to subscriber of other NationalAccounts. Conventional throttling techniques may be used for thispurpose.

Referring now to FIGS. 5 and 6, exemplary embodiments of the presentinvention for providing over-the-air programming of the PSL/IRDB to themobile station will be described. In accordance with the invention,over-the-air programming of the PSL/IRDB may be accomplished as part ofthe Over-the-Air Activation Teleservice (OATS) defined in the Addendumto Interim Standard 136A (IS-136A) of the North American CellularSystem, or as a different teleservice. A teleservice is generally anend-to-end data application between a mobile station and a networkentity (e.g., a message center or Over-the-Air Activation Function(OTAF)) that is typically independent of and transparent to a BaseStation/Mobile Switching Center/Interworking Function (BMI). The BMIprovides the teleservice transport, but is not directly involved inprocessing the actual teleservice data. For additional informationconcerning OATS, OTAF and BMI, see the Addendum to IS-136 Revision Acontained in TIA/EIA/IS-136.1-A-1, Addendum No. 1 to TIA/EIA/IS-136.1-A,Telecommunications Industry Association, November 1996, the disclosureof which is expressly incorporated herein by reference in its entirety.For information on over-the-air activation (OAA) and over-the-airprogramming (OAP), see "BellSouth Cellular and Southwestern Bell JointRequirements Document: Interim Over-The-Air Activation for 850 MHzIS-136 Mobile Stations", Version 1.1, Feb. 17, 1997, and "IntelligentRoaming", Contribution Submitted by AT&T Wireless Services, Inc. to TIATR45.3.6, Apr. 28-30, 1997, the disclosures of which are expresslyincorporated herein by reference in their entireties.

According to one embodiment of the present invention, the over-the-airprogramming of the PSL/IRDB may be made part of OATS, by standardizingand providing new information elements to program the mobile stationwith the PSL/IRDB, i.e., the intelligent roaming data (see, for example,FIG. 5 and the accompanying description provided below). Alternatively,in accordance with another embodiment of the present invention, theover-the-air programming of the PSL/IRDB may be made part of the OATS byembedding the new information as messages within the System OperatorCode (SOC) Specific Request message defined for OATS. The SystemOperator Code (SOC) is a twelve bit value that is broadcasted on thecontrol channel (normally a DCCH) and used to identify which operator isproviding service. In the two embodiments described below, if a PSL/IRDBentry is duplicative of another PSL/IRDB entry stored in the mobilestation, then a new PSL/IRDB entry may overwrite the old PSL/IRDB entryin memory. In addition, if there is a large quantity of PSL/IRDBinformation that needs to be stored in the mobile station, the initialdownloading of all of the PSL/IRDB information may be performed by aphysical interface or connection (e.g., during manufacture of the mobilestation), and subsequent updates or reprogramming of specific data inthe PSL/IRDB may be performed over-the-air.

FIG. 5 illustrates, in accordance with an embodiment of the presentinvention, an exemplary diagram of message flows between a MobileStation (MS) and the Base Station/Mobile Switching Center/InterworkingFunction (BMI) for implementing over-the-air programming of the PSL/IRDBbased on OATS. The MS comprises a station used by a cellular or PCSsubscriber to access network services over an air interface. The MS maybe implemented as a portable phone unit, a unit installed in a vehicleor a fixed subscriber station. Base stations provide the ability foreach MS to access network services over an air interface. An MSC or MTSOis connected to at least one base station, and may use inter-workingfunctions to connect to other networks.

According to an aspect of the present invention, the BMI includes thenetwork entity that stores a centralized or master PSL/IRDB database,and that oversees the programming of the PSL/IRDB in each of the mobilestations. The same network entity that provides OATS may also providethe over-the-air programming of the PSL/IRDB for the mobile stations.OATS may be used on either a Digital Traffic Channel (DTC) or a DigitalControl Channel (DCCH). If there is a large quantity of PSL/IRDBinformation to be programmed, multiple Download Request messages may besent to the mobile station in order to program all of the intelligentroaming data. In FIG. 5, CSC is an acronym for the Customer ServiceCenter, and NAM is an acronym for Number Assignment Module in the mobilestation.

According to the embodiment of FIG. 5, the existing OATS messages areused for over-the-air programming of the PSL/IRDB in the mobile station.However, new information elements and fields are defined, according tothe present invention, for some of the OATS messages in order to programthe mobile station with the PSL/IRDB information. The particular OATSmessages that are modified to incorporate the PSL/IRDB informationinclude, for example, the Confirmation Data Request, the ConfigurationData Response, the Download Request, and the Download Result messages,which are indicated in FIG. 5 and discussed in detail below.

When a Configuration Data Request message is sent from the BMI to the MSat step S.200, specific configuration data blocks are solicited from themobile station. An example of the contents of a modified ConfigurationData Request message, according to an aspect of the invention, isindicated below in Table 5. In Table 5, and in the subsequent tablesdiscussed below, the "Type" may be either Mandatory (M) or Optional (O),and the "Length" is given in bits. Further, for Table 5 and thesubsequent tables provided herein, the new information elements andmodifications to the OATS-based messages are underlined in the tables.

                  TABLE 5                                                         ______________________________________                                        Configuration Data Request                                                    Information Element  Type   Length                                            ______________________________________                                        Message Type         M      6                                                 Remaining Length (in Octets)                                                                       M      8                                                 Configuration Data Block Map                                                                       M      16                                                ______________________________________                                    

As shown in Table 5, the Configuration Data Request may be modified toinclude a new entry in the Configuration Data Block Map. TheConfiguration Data Block Map is an information element or data messagethat provides a list of the Configuration Data Blocks for which the BMIrequests configuration information from the MS. As shown below inexemplary embodiment of Table 6, the Configuration Data Block Map mayinclude specific values for a NAM Configuration Data Block request and aNon-Public System Configuration Data Block request. In addition,according to the present invention, values may be provided for a BandInfo request and System Access List request for the purpose ofprogramming the mobile station. A more detailed discussion of the BandInfo and System Access List data blocks of the present invention isprovided below. In Table 6, and the subsequent tables, the value "X"(where present) represents that the value may be assigned either a valueof zero or value of one.

                  TABLE 6                                                         ______________________________________                                        Configuration Data Block Map                                                  Value        Function                                                         ______________________________________                                        XXXX XXXX XXXX                                                                             NAM Configuration Data Block requested                           XXX1                                                                          XXXX XXXX XXXX                                                                             Non-Public System Configuration Data Block                       XX1X         requested                                                        XXXX XXXX XXXX                                                                             Band Info requested                                              X1XX                                                                          XXXX XXXX XXXX                                                                             System Access List requested                                     1XXX                                                                          ______________________________________                                         All other values may be reserved                                         

At step S.204, a CSC Challenge Request is sent from the MS to the BMI inresponse to receiving the Configuration Data Request. The CSC ChallengeRequest that is sent by the MS may be similar to the OATS-based CSCChallenge Request. Following step S.204, an OATS-based CSC ChallengeResponse is sent by the BMI at step S.208 in response to the CSCChallenge Request from the MS, and then a Configuration Data Response issent at step S.212. While the OATS-based CSC Challenge Request and theCSC Challenge Response are not modified, the standard Configuration DataResponse message for OATS is modified, according to the presentinvention, with new information elements so that the mobile station canprovide, for example, information to the BMI on the currently storedintelligent roaming information (i.e., Band Info and PSL/IRDB). Table 7Ashows an exemplary configuration of the modified Configuration DataResponse, and Table 7B illustrates exemplary parameter type codes forthe optional information elements in the Configuration Data Response ofTable 7A, in accordance with an aspect of the invention. In Table 7A,and the subsequent tables, the "*" represents that the maximum bitlength or range of the bit length is only limited by the defined lengthof the overall application layer message.

                  TABLE 7A                                                        ______________________________________                                        Configuration Data Response                                                   Information Element  Type   Length                                            ______________________________________                                        Message Type         M       6                                                Remaining Length (in Octets)                                                                       M       8                                                NAM Configuration Data Block                                                                       0      8 or 212-648                                      Non-Public Configuration Data Block                                                                0      12-*                                              System Operator Code (SOC)                                                                         0      16                                                Index Code           0      36                                                Band Info            0      27                                                System Access List   0      35-*                                              ______________________________________                                    

                  TABLE 7B                                                        ______________________________________                                        Parameter Codes for Optional Information Elements                             Parameter Type        Code                                                    ______________________________________                                        NAM Configuration Data Block                                                                        0001                                                    Non-Public Configuration Data Block                                                                 0010                                                    System Operator Code (SOC)                                                                          0011                                                    Index Code            0100                                                    Band Info             0101                                                    System Access List    0110                                                    ______________________________________                                    

As shown in Table 7A, the Configuration Data Response message of thepresent invention is similar to the Configuration Data Response for OATSexcept that for the invention a Band Info information element and aSystem Access List information element are also included in the message.The Band Info information element may contain data that identifies, forexample, the home band and the secondary band, as well as other data tosupport intelligent roaming. The System Access List information elementmay contain PSL/IRDB data entries for the mobile station to use inidentifying the preferred system(s) to access in an intelligent roamingmode. Examples of the data fields for the Band Info and System AccessList information elements are provided below with reference to Tables 9and 14, respectively. Exemplary parameter type codes that may be usedfor the optional information elements of the Configuration Data Responseof Table 7A are provided in Table 7B. As shown in Table 7B, newparameter type codes may be provided for the Band Info and the SystemAccess List information elements.

Referring to FIG. 5, after the Configuration Data Response message hasbeen sent to the BMI, a Download Request message is sent to the MS atstep S.216. The Download Request message is sent to the mobile stationin order to download specific configuration data. According to thepresent invention, the Download Request message may be modified toinclude the Band Info and System Access List information elements. Anexample of the modified Download Request Message is shown in Table 8A,and Table 8B includes exemplary parameter type codes that may be usedfor the optional information elements in the Download Request message ofTable 8A.

                  TABLE 8A                                                        ______________________________________                                        Download Request                                                              Information Element Type   Length                                             ______________________________________                                        Message Type        M      6                                                  Remaining Length (in Octets)                                                                      M      8                                                  NAM Download        0      *                                                  Non-Public Download 0      *                                                  Band Info           0      26                                                 System Access List  0      35-*                                               ______________________________________                                    

                  TABLE 8B                                                        ______________________________________                                        Parameter Codes for Optional Information Elements                             Parameter Type    Code                                                        ______________________________________                                        NAM Download      0001                                                        Non-Public Download                                                                             0010                                                        Band Info         0011                                                        System Access List                                                                              0100                                                        ______________________________________                                    

The Band Info information element that is provided as part of theConfiguration Data Response message and Download Request message may beused to identify, for example, the home band, the probability block mapfor the home band, and the secondary band to support the intelligentroaming capabilities of the present invention. The Band Info informationelement is a new OATS information element. Table 9 illustrates anexample of a Band Info information element, according to an aspect ofthe present invention.

                  TABLE 9                                                         ______________________________________                                        Band Info                                                                     Field             Length                                                      ______________________________________                                        Parameter Type    4                                                           SID Alpha Tag Control                                                                           1                                                           Home Band         3                                                           Probability Block Map                                                                           16                                                          Secondary Band    3                                                           ______________________________________                                    

In the Band Info information element, a Parameter Type code (e.g., 0011)may be included to indicate the parameter type, and a SID Alpha TagControl field (i.e., a SAT₋₋ Ctrl field) may be included to indicatewhen the Home SID Alpha Tag should be displayed. If, for example, theSID Alpha Tag Control field is set to one, then the mobile station willbe instructed to display the Home SID Alpha Tag. If, on the other hand,the SID Alpha Tag Control field is set to zero, the Home SID Alpha Tagwill not be displayed. A Home Band field may also be provided in theBand Info information element to indicate the frequency band for thehome system. Further, as shown in Table 9, a Probability Block Map fieldmay also be provided to indicate the most likely probability blocks inwhich a control channel may be found by the mobile station. Tables 12and 13 are, respectively, exemplary Home Band and Probability Block Mapfields that may be utilized to implement the features of the presentinvention.

As further shown in Table 9, the Band Info information element mayinclude a Secondary Band field. The Secondary Band field may be providedto identify the secondary frequency band for the mobile station to scanif no acceptable control channels can be found on the home band. TheSecondary Band field may be coded in a similar manner to the Home Bandfield described below (see, for example, Table 12).

In response to the Download Request message from the BMI at step S.216,a Download Result message is sent at step S.220 from the MS to the BMI.In accordance with the present invention, the Download Result messagemay be a modified OATS message that includes a Download Result Mapinformation element. The Download Result Map information elementprovides feedback to the BMI on the results of the data block downloads.Table 10A illustrates an exemplary, modified Download Result message,and Table 10B illustrates exemplary parameter type codes of the optionalinformation elements in the Download Result message of Table 10A. Inaddition, Table 11 is an exemplary Download Result Map informationelement which may be provided as part of the Download Result message ofTable 10A.

                  TABLE 10A                                                       ______________________________________                                        Download Result                                                               Information Element Type   Length                                             ______________________________________                                        Message Type        M      6                                                  Remaining Length (in Octets)                                                                      M      8                                                  Download Result Map M      16                                                 Parameter Error     0      *                                                  ______________________________________                                    

                  TABLE 10B                                                       ______________________________________                                        Parameter Codes for Optional Information Elements                                    Parameter Type                                                                          Code                                                         ______________________________________                                               Parameter Error                                                                         0001                                                         ______________________________________                                    

                  TABLE 11                                                        ______________________________________                                        Download Result Map                                                           Value        Function                                                         ______________________________________                                        XXXX XXXX XXXX                                                                             NAM download unsuccessful                                        XXX0                                                                          XXXX XXXX XXXX                                                                             NAM download successful                                          XXX1                                                                          XXXX XXXX XXXX                                                                             Non-Public download unsuccessful                                 XX0X                                                                          XXXX XXXX XXXX                                                                             Non-Public download successful                                   XX1X                                                                          XXXX XXXX XXXX                                                                             Band Info download unsuccessful                                  X0XX                                                                          XXXX XXXX XXXX                                                                             Band Info download successful                                    X1XX                                                                          XXXX XXXX XXXX                                                                             System Access List download unsuccessful                         0XXX                                                                          XXXX XXXX XXXX                                                                             System Access List download successful                           1XXX                                                                          ______________________________________                                         All other values may be reserved                                         

After step S.220 in FIG. 5, the subsequent OATS messages may be sent instandardized format to complete the over-the-air programming of themobile station. That is, at step S.224, a NAM Commit Result message maybe sent from the BMI to the MS, and then a CSC Challenge Request messagemay be sent at step S.228 from the MS to the BMI. Thereafter, at stepS.232, a CSC Challenge Response message may be sent to the MS, and thena NAM Commit Result may be sent from the MS to the BMI in step S.236. Atthis point, the PSL/IRDB and other intelligent roaming data is updatedin the memory of the MS, and the MS may proceed to perform intelligentroaming with the updated information.

As described above, the message flow for over-the-air programming of themobile station may be achieved by utilizing new information elementsthat are sent based on an OATS message flow. According to an aspect ofthe present invention, the existing OATS messages that are modified toinclude these new information elements include, for example, theConfiguration Data Request message, the Configuration Data Responsemessage, the Download Request message and the Download Result message,as described above. The new and modified OATS information elements thatare provided include, for example, the Band Info information element,which is described above with reference to Table 9, the ConfigurationData Block Map information element, which is described above withreference to Table 6, and the Download Result Map information element,which is described above with reference to Table 11. Other newinformation elements and fields may also be provided to implement theintelligent roaming capabilities of the present invention. Examples ofthese information elements and fields are discussed below with referenceto Tables 12-19.

Table 12 illustrates an exemplary list of coded values for the Home Bandfield, which may be provided as one of the fields in the Band Infoinformation element (see, for example, Table 9). As discussed above, theHome Band field may indicate the frequency band for the home system ofthe mobile station. The Home Band field may be three bits in length andassigned one of a plurality of coded values to indicate the frequencyband of the home network provider. As shown in Table 12, values may beassigned for both cellular A and B bands, as well as for 1900 MHZ PCSbands.

                  TABLE 12                                                        ______________________________________                                        Home Band                                                                     Value             Function                                                    ______________________________________                                        000               800 MHZ A Band                                              001               800 MHZ B Band                                              010               1900 MHZ A Band                                             011               1900 MHZ B Band                                             100               1900 MHZ C Band                                             101               1900 MHZ D Band                                             110               1900 MHZ E Band                                             111               1900 MHZ F Band                                             ______________________________________                                    

Table 13 illustrates an exemplary coding of values for the ProbabilityBlock Map field. The Probability Block Map field may be provided as oneof the fields in the Band Info information element, as discussed abovewith reference to Table 9. The Probability Block Map field indicates themost likely probability blocks in which a control channel may be foundby the mobile station. The probability block members may be defined inaccordance with Interim Standard 136.1 (IS-136.1), Revision A, Section6.3.1.1.1 for each frequency band. For more information on IS-136.1, seefor example TIA/EIA-IS-136.1-A, TDMA Cellular/PCS-Radio Interface-MobileStation-Base Station Compatibility-Digital Control Channel,Telecommunications Industry Association, October 1996, the disclosure ofwhich is expressly incorporated herein by reference in its entirety.

                  TABLE 13                                                        ______________________________________                                        Probability Block Map                                                         Value    Function                                                             ______________________________________                                        1XXX XXXX                                                                              1st probability block likely to contain control channels             XXXX XXXX                                                                     0XXX XXXX                                                                              1st probability block unlikely to contain control channels           XXXX XXXX                                                                     .        .                                                                    .        .                                                                    .        .                                                                    XXXX XXXX                                                                              16th probability block likely to contain control channels            XXXX XXX1                                                                     XXXX XXXX                                                                              16th probability block unlikely to contain control                   XXXX XXX0                                                                              channels                                                             ______________________________________                                    

Table 14 illustrates the various fields that may be provided for theSystem Access List information element. As discussed above, the SystemAccess List information element may be included in the ConfigurationData Response message (see step S.212) and the Download Request message(see step S.216). The System Access List information element may containPSL/IRDB entries for the mobile station to use in identifying thepreferred system to access when in an intelligent roaming mode. As shownin Table 14, the System Access List information element may include afield to indicate the number of PSL/IRDB entries that are present (e.g.,a Number of Target Systems field), and may include one or more PSL/IRDBentries that are provided for each SID included in the System AccessList information element. The System Access List information element mayalso include a coded Parameter Type field (e.g., 0100) to indicate theparameter type. Table 15 illustrates an example of the fields for anPSL/IRDB entry, which is used to indicate the target or preferredsystems for the mobile station when roaming.

                  TABLE 14                                                        ______________________________________                                        System Access List                                                            Field                Length                                                   ______________________________________                                        Parameter Type       4                                                        Number of PSL/IRDB Entries (S)                                                                     7                                                        PSL/IRDB Entry (S + 1 instances of this                                                            (S + 1) × (24 + 40 × T)                      field are present)                                                            ______________________________________                                    

                  TABLE 15                                                        ______________________________________                                        PSL/IRDB Entry                                                                Field                      Length                                             ______________________________________                                        Current SID                15                                                 Roam Indicator             1                                                  Scan Method                2                                                  Scan Time                  2                                                  Number of Target Systems (T)                                                                             4                                                  Target System Info (T instances of this field are present)                                               (40 × T)                                     ______________________________________                                    

As shown in Table 15, each PSL/IRDB entry may include a Current SIDfield to indicate the current SID that the entry is associated with, aRoam Indicator field to indicate the status of the roam indicator, aScan Method field to indicate the scan method to be utilized by themobile station, a Scan Time field to indicate the scan time, a Number ofTarget Systems field to indicate the number of preferred or targetsystems, and a Target System Info field for each target system. EachPSL/IRDB entry may be accessed by the mobile station by looking up theSID of the current system and comparing it with the Current SID field ofeach entry in the System Access List until a match is found. The RoamIndicator field may be used in each PSL/IRDB entry to indicate whetherthe roam indicator should be displayed by the mobile station for thecurrent system. For example, when the Roam Indicator field is set toone, this field will indicate that the mobile station should display theroam indicator. If, however, the Roam Indicator field is set to zero,the roam indicator should not be displayed by the mobile station.

The Scan Method field of each PSL/IRDB entry may indicate how the mobilestation should scan for a target system. Table 16 illustrates an exampleof the coded values that may be assigned to the Scan Method bit field,as well as the related function for each coded value. If, for example,the Scan Method field has a value of zero, then the mobile stationshould perform a continuous scan until it finds a target system. If, onthe other hand, the Scan Method field is equal to one, then the mobilestation should obtain service on the current SID and scan for target orpreferred systems periodically.

                  TABLE 16                                                        ______________________________________                                        Scan Method                                                                   Value   Function                                                              ______________________________________                                        00      Continuous scan until find a target system                            01      Obtain service on current SID and scan for target systems                     periodically                                                          All other values may be reserved                                              ______________________________________                                    

The Scan Time field of each PSL/IRDB entry indicates the approximateinterval between scans for a target system. Table 17 illustrates variouscoded values that may be assigned to the Scan Time field. The scan timeinterval may be set based upon various factors, including the operatingconditions of the mobile station. For example, the battery power of themobile station may effect the scan time interval, such that a longerscan time interval may be desirable to reduce the number of requiredscans and consumption of the battery. By way of a non-limiting example,a scan time interval of two and one-half or five minutes may beutilized. As shown in the embodiment of Table 17, if the Scan Time fieldis set to zero, then the scan time will be set such that the mobilestation will perform a scan every two and one-half minutes. If the scantime is set to one, then a longer scan time may be used by the mobilestation. For example, in Table 17, a scan time field value of one wouldcause the mobile station to perform a periodical scan every fiveminutes.

                  TABLE 17                                                        ______________________________________                                        Scan Time                                                                     Value        Function                                                         ______________________________________                                        00           Periodically scan every 21/2 minutes                             01           Periodically scan every 5 minutes                                All other values may be reserved                                              ______________________________________                                    

As noted above, each PSL/IRDB entry may include a field to indicate thenumber of target systems (i.e., a Number of Target Systems field), and afield to indicate the target system information for each target system(i.e., a Target System Info field). Target system information may beprovided for each target or preferred system that exists for the currentSID. The number of target systems for a current SID will vary dependingupon, for example, the reciprocal agreements or billing arrangementsthat the home network provider has with providers for the current SID.Table 18 illustrates an exemplary Target System Info field and theinformation that may be included in the Target System Info field.

                  TABLE 18                                                        ______________________________________                                        Target System Info                                                            Field             Length                                                      ______________________________________                                        Target Band       3                                                           Technology Map    5                                                           Target SID        15                                                          Roam Indicator    1                                                           Probability Block Map                                                                           16                                                          ______________________________________                                    

As shown in Table 18, the Target System Info may include a Target Bandfield which identifies the frequency band for a target or preferredsystem. The Target Band field may be coded in a similar manner to theHome Band field (see, for example, Table 12). A field to indicate theSID of the target system (i.e., a Target SID field), as well as a fieldto indicate the roam indicator display status for the target system(i.e., a Roam Indicator field) may also be provided. The Roam Indicatorfield of the Target System Info may indicate to the mobile station whena roaming status indication should be displayed when service is obtainedon a particular target system. When the Roam Indicator field is set toone, for example, this field may indicate that the mobile station shoulddisplay the roaming status indication. Otherwise, if the value of theRoam Indicator field is set to zero, the roaming status indicationshould not be displayed by the mobile station.

As part of the target system information in the Target System Info datablock, a Technology Map field may also be provided. The Technology Mapfield may identify the air-interface technologies (e.g., EIA/TIA-553(AMPS), IS-136, PCS-1900, etc.) and/or other technologies associatedwith a particular frequency band of a given target system. Table 19illustrates examples of the various coded values that the Technology Mapfield may be assigned to indicate a particular air-interface technology.In the embodiment of Table 19, the unassigned bit values may be held inreserve for future systems or applications (e.g., they could be assignedto PACS, CDMA, or other technologies).

                  TABLE 19                                                        ______________________________________                                        Technology Map                                                                Value          Function                                                       ______________________________________                                        XXXX1          EIA/TIA-553 (AMPS)                                             XXX1X          IS-136                                                         XX1XX          PCS-1900                                                       All other values may be reserved                                              ______________________________________                                    

Other information relating to each target or preferred system may alsobe provided as part of the information fields for the Target SystemInfo. For example, a Probability Block Map field may be provided toindicate the most likely probability blocks in which a control channelmay be found. An example of the manner in which a Probability Block Mapfield may be coded is provided above with reference to Table 13.

In accordance with another embodiment of the present invention, thePSL/IRDB and intelligent roaming information may be downloaded andprogrammed into the mobile station by embedding the over-the-airprogramming messages within the SOC Specific Request message defined forOATS. According to this embodiment, the BMI will send the SOC SpecificRequest message to the mobile station (MS), and the MS will respond withthe R* DATA ACCEPT message. FIG. 6 illustrates an example of the messageflow between the MS and the BMI for over-the-air programming of themobile station in accordance with this embodiment of the presentinvention.

In the embodiment of FIG. 6, the intelligent roaming data will only becommitted to memory in the mobile station following a NAM Commit Requestmessage from the BMI, and a successful CSC Challenge. If needed,multiple SOC Specific Request messages may be sent to the MS prior to aNAM Commit Request in order to program all of the intelligent roamingdata.

At step S.300 in FIG. 6, an SOC Specific Request message is sent fromthe BMI to the MS. The SOC Specific Request message may be used for SOCSpecific Data. Table 16 illustrates an example of the informationelements that may be included in each SOC Specific Request message. Asshown in Table 20, the SOC Specific Request message may be configuredaccording to the existing message defined for OATS.

                  TABLE 20                                                        ______________________________________                                        SOC Specific Request                                                          Information Element Type   Length                                             ______________________________________                                        Message Type        M      6                                                  Remaining Length (in Octets)                                                                      M      8                                                  System Operator Code (SOC)                                                                        M      12                                                 SOC Specific Data   M      0-*                                                ______________________________________                                    

As shown in step S.304 of FIG. 6, multiple SOC Specific Request messagesmay be sent to the mobile station prior to the NAM Commit Request, inorder to program all of the necessary intelligent roaming data. Each SOCSpecific Request message may be used for SOC Specific Data. The SOCSpecific Data may be provided as an information element in each of theSOC Specific Request messages. Table 21A illustrates the variousinformation elements and coded contents that may be provided as the SOCSpecific Data. When messages are sent, the SOC may be set to aparticular code corresponding to the service provider (e.g., 004 hex).The SOC Specific Data may include the Band Info and the System AccessList information elements, similar to that described above (see, forexample, Tables 9, 14 and 15). Table 21B illustrates an example of theparameter type codes for the optional information elements in the SOCSpecific Data information element of Table 21A.

                  TABLE 21A                                                       ______________________________________                                        SOC Specific Data                                                             Information Element                                                                              Type   Length                                              ______________________________________                                        Band Info          0      26                                                  System Access List 0      35-*                                                ______________________________________                                    

                  TABLE 21B                                                       ______________________________________                                        Parameter Codes for Optional Information Elements                             Parameter Type   Code                                                         ______________________________________                                        Band Info        0001                                                         System Access List                                                                             0010                                                         ______________________________________                                    

After all of the SOC Specific Request messages have been sent, a NAMCommit Request message may be sent from the BMI to the MS at step S.308.In response, a SOC Challenge Request message will be sent from the MS tothe BMI at step S.312, and a CSC Challenge Response will be returned bythe BMI to the MS at step S.316. Thereafter, as shown in FIG. 6, a NAMCommit Result message will be sent at step S.320 from the MS to the BMIto confirm the programming of the intelligent roaming data to the mobilestation.

Various techniques and network architectures may be utilized foradministering, programming and updating each mobile station with thePSL/IRDB and other intelligent roaming information. For example, asdiscussed above, a main or centralized database could be established toimplement the various aspects of the present invention. Such acentralized database could include information on all of the networksystems that the home service provider owns, as well as information onall the systems with which the service provider has preferred roamingagreements or billing arrangements. Entries in the database couldencompass, for example, all of the information that is provided to themobile station as part of the over-the-air programming of the mobilestation. Other information could also be included in such a centralizeddatabase. For example, the centralized database could contain for eachentry in the PSL/IRDB, the name of the cellular service provider foreach target or preferred system, a contact, and roaming agreementinformation.

In accordance with another aspect of the present invention, FIG. 7illustrates an exemplary network architecture for implementing andadministering the intelligent roaming capabilities and features of thepresent invention. In the embodiment of FIG. 7, a mobile station 168receives PSL/IRDB information via a centralized or master PSL/IRDBdatabase 192 that has one or more slave PSL/IRDB database arrangements186. The master PSL/IRDB 192 may be administered centrally by anoperator and may contain PSL/IRDB information and other intelligentroaming information for all of the systems that the service providerowns, and all of the systems with which the service provider haspreferred roaming agreements. The master PSL/IRDB 192 may comprise acomputer or workstation with memory, and a database application forstoring all of the PSL/IRDB information and other intelligent roaminginformation. The master PSL/IRDB 192 may also include a database thatindicates all of the mobile stations supporting the intelligent roamingcapabilities of the present invention.

Each of the slave PSL/IRDBs 186 may comprise logical entities within,for example, an Over-The-Air Activation Function (OTAF). The OTAF maycomprise a software application residing on a computer or workstation,and be adapted to store and forward information to be programmed intothe mobile stations. The master PSL/IRDB 192 may update all OTAF/slavePSL/IRDBs 186 with new information concerning target or preferredsystems as required or as information becomes available. When the masterPSL/IRDB 192 is updated with new PSL/IRDB information, each of theOTAF/slave PSL/IRDBs 186 may receive the information from the masterPSL/IRDB 192 through, for example, a Transmission ControlProtocol/Internet Protocol (TCP/IP) connection, format the informationfor the mobile stations, and send the formatted information to themobile stations through the cellular or PCS network. Along with the newPSL/IRDB information sent from the master PSL/IRDB 192, a list of themobile stations requiring updating may be sent to all OTAF/slavePSL/IRDBs 186. Each of the OTAF/slave PSL/IRDBs 186 would then beresponsible for updating the mobile stations, and may keep track of themobile stations that have been updated with new intelligent roaminginformation and those that still require updating. Each of the mobilestations may be identified by its Mobile Identification Number (MIN) orInternational Mobile Station Identity (IMSI). The mobile stationidentity may also identify the mobile station's Home Location Register(HLR).

As noted above, each of the OTAF/slave PSL/IRDBs 186 may send theformatted information to the mobile stations through the cellular or PCSnetwork. The Base Station/Mobile Switching Center/Inter-Working Function(BMI) may be used to transfer the information to the mobile stations.When information is received from the master PSL/IRDB 192, theOTAF/slave PSL/IRDB 186 may send, for example, an Interim Standard 41C(IS-41C) message to the mobile station's HLR to determine the locationof the mobile station. The HLR may then respond with an address for theserving systems's MSC or MTSO (such as MTSO 154). As illustrated in FIG.7, the OTAF/slave PSL/IRDB 186 may then communicate over-the-airprogramming messages for the mobile station, such as mobile station 168,via MTSO 154 using the IS-41C SMS Delivery Point-to-Point (SMDPP)message. The MTSO 154 may then repackage the over-the-air message into,for example, an Interim Standard 136 (IS-136) R-DATA message fordelivery to the mobile station 168 through an appropriate base stationor cell site 175. Feedback may be provided by the serving MTSO 154 tothe OTAF/slave PSL/IRDB 186 (e.g., in the form of another IS-41Cmessage) to indicate whether the information successfully reached themobile station. If the information was not successfully delivered to themobile station, the OTAF/slave PSL/IRDB 186 could trigger a retrymechanism to resend the information.

Other features may be provided for administering and implementing theintelligent roaming capabilities of the present invention. For example,as an alternative to the embodiment of FIG. 7, the home network systemcould broadcast a code indicating when the central PSL/IRDB database waslast updated. Based on this code, mobile stations could then determineperiodically if they have the most current PSL/IRDB information. When itis determined that the PSL/IRDB information contained in the mobilestation is not current, the mobile station could request reprogrammingby sending a request message using, for example, OATS message protocols.

While the invention has been described with reference to severalexemplary embodiments, it is understood that the words which have beenused herein are words of description and illustration, rather than wordsof limitations. Changes may be made, within the purview of the appendedclaims, as presently stated and as amended, without departing from thescope and spirit of the invention in its aspects.

For example, although a mobile station-based approach has been disclosedfor implementing the intelligent roaming features and capabilities ofthe present invention, other approaches and methods may be utilized toachieve and implement the various aspects of the present invention. Forexample, the present invention may be implemented through anetwork-based approach, whereby PSL/IRDB and preferred systeminformation is directed from a serving network to the mobile station inorder to obtain service on the preferred system. In such a case, some ormost of the "intelligence" may be provided in the network to facilitateroaming by the mobile station.

Further, although embodiments for over-the-air programming of thePSL/IRDB have been discussed with reference to OATS, over-the-airprogramming may be implemented as a different or separate teleservice.For example, over-the-air programming may be developed and standardizedas a completely new teleservice, or it may be developed as acarrier-specific teleservice. In addition, various over-the-airactivation methods or teleservices, including OATS, may be utilized inorder to activate new mobile station users. For example, activationinformation may be programmed in the mobile station using the DigitalControl Channel (DCCH) that is associated with IS-136, or an appropriatesignaling channel to communicate with a cellular network when not on avoice or data call. Alternatively, the activation information may beprogrammed in the mobile station using a Digital Traffic Channel (DTC),or an appropriate digital voice or data channel to communicate with acellular network. If over-the-air activation is performed on the DCCH orthe DTC, the new mobile station user may be required to initiate a callto a Customer Service Center (CSC), and to follow a predetermined set ofprocedures to perform over-the-air activation of the mobile station.

Although the invention has been described herein with reference toparticular means, materials and embodiments, the invention is notintended to be limited to the particulars disclosed herein; rather, theinvention extends to all functionally equivalent structures, methods anduses, such as are within the scope of the appended claims.

What is claimed:
 1. An apparatus for providing preferred wirelesscarrier information for use by a mobile station when the mobile stationis roaming outside of a home market area of the mobile station, theapparatus comprising:a database that identifies preferred wirelesscarriers for a plurality of market areas based upon predeterminedclasses of service; a generator that generates a list of preferredwireless carrier identities from the database based upon a selectedclass of service of the mobile station; and a data-providing device thatprovides the generated list to the mobile station designated with theselected class of service.
 2. The apparatus of claim 1, wherein thedatabase further comprises a plurality of predetermined home marketareas, the generated list of preferred wireless carrier identities beingbased upon the selected class of service and a selected one of theplurality of home market areas.
 3. The apparatus of claim 2, wherein thedata providing device provides the generated list to the mobile stationdesignated with the selected class of service and the selected homemarket area.
 4. The apparatus of claim 1, wherein the database furthercomprises a plurality of national accounts, the generated list ofpreferred wireless carrier identities being based upon the selectedclass of service and a selected one of the national accounts.
 5. Theapparatus of claim 4, wherein the data providing device provides thegenerated list to the mobile station designated with the selected classof service and the selected national account.
 6. The apparatus of claim1, wherein the list includes an alternative carrier for use in the eventthe preferred wireless carrier is not available to the mobile station.7. The apparatus of claim 1, wherein the data providing device providesthe list of preferred wireless carrier identities to the mobile stationvia wireless communication.
 8. The apparatus of claim 1, wherein thelist of preferred wireless carriers is generated by said generator basedupon a roaming airtime rate of each of the plurality of wirelesscarriers and air-interface technology provided for each of the pluralityof market areas.
 9. The apparatus of claim 1, wherein said generatorupdates the list of preferred wireless carriers when one of theplurality of wireless carriers changes a communication characteristicfor one of the plurality of market areas.
 10. The apparatus of claim 9,wherein said data providing device provides the updated list ofpreferred wireless carrier identities only to each mobile stationpreviously provided with the list of preferred wireless carrieridentities.
 11. The apparatus of claim 9, wherein the communicationcharacteristic comprises roaming airtime rates the wireless carriercharges for the one of the plurality of market areas.
 12. The apparatusof claim 9, wherein the communication characteristic comprises the typeof services the wireless carrier provides for the one of the pluralityof market areas.
 13. The apparatus of claim 1, wherein the mobilestation is assigned to one of the predetermined classes of service basedupon services to which the mobile station subscribes.
 14. The apparatusof claim 1, wherein the list of preferred wireless carrier identitiescomprises a plurality of entries indicating a system identificationnumber and a corresponding frequency band for each preferred wirelesscarrier.
 15. An apparatus for providing preferred wireless carrierinformation for use by a mobile station when the mobile station isroaming outside of a home market area of the mobile station, theapparatus comprising:a database that includes preferred wirelesscarriers for a plurality of market areas based upon predeterminedclasses of service; means for generating a list of preferred wirelesscarrier identities from the database based upon a selected class ofservice of the mobile station; and means for providing the generatedlist to the mobile station designated with the selected class ofservice.
 16. The apparatus of claim 15, wherein the database furthercomprises a plurality of predetermined home market areas, the generatedlist of preferred wireless carriers being based upon the selected classof service and a selected one of the plurality of home market areas. 17.The apparatus of claim 15, wherein the database further comprises aplurality of national accounts, the generated list of preferred wirelesscarriers being based upon the selected class of service and a selectedone of the national accounts of the mobile station.
 18. The apparatus ofclaim 15, wherein the generating means updates the list of preferredwireless carriers when one of the plurality of wireless carriers changesa communication characteristic for one of the plurality of market areas,said communication characteristic comprising at least one of a wirelesscarrier's roaming airtime rate and an air interface technology of awireless carrier.
 19. The apparatus of claim 18, wherein the providingmeans provides the updated list of preferred wireless carrier identitiesto the mobile station previously provided with the list of preferredwireless carrier identities.
 20. A mobile station, comprising:a memorythat stores a list of preferred wireless carrier identities for use bythe mobile station when roaming, said list of preferred wireless carrieridentities being stored based upon a selected class of service for aplurality of market areas; and a selector that automatically selects apreferred wireless carrier from the list stored in said memory when themobile station is roaming and enters one of the market areas of theplurality of market areas.
 21. The mobile station of claim 20, whereinthe mobile station switches to a preferred wireless carrier, selectedfrom the list of preferred wireless carrier identities, to use forcommunication in response to the mobile station roaming to one of theplurality of market areas.
 22. The mobile station of claim 20, whereinthe list of preferred wireless carrier identities is downloaded to thememory of the mobile station from a message center.
 23. The mobilestation of claim 22, wherein the list of preferred wireless carrieridentities is downloaded to the memory via a communications linkestablished between the message center and the memory of the mobilestation.
 24. The mobile station of claim 23, wherein the communicationslink comprises a wireless communications link.
 25. The mobile station ofclaim 23, wherein the communications link comprises a wiredcommunications link.
 26. The mobile station according to claim 20,wherein the list comprises a preferred wireless carrier and analternative wireless carrier for at least one market area of theplurality of market areas.
 27. An system for selecting preferredwireless carriers from a plurality of wireless carriers for use bymobile stations when roaming outside of a home market area of the mobilestation, the system comprising:a database of preferred wireless carriersfor a plurality of market areas based upon predetermined classes ofservice; a generator that generates a list of the preferred wirelesscarrier identities from the database based upon a selected class ofservice of each mobile station; a data-providing device that providesthe generated list to each mobile station designated with the selectedclass of service; a memory, provided within each mobile station, whichstores the generated list of preferred wireless carriers; and a selectorthat selects a preferred wireless carrier from the list stored in thememory when each mobile station enters one of the market areas of theplurality of market areas, wherein each mobile station switches to thepreferred wireless carrier, selected from the list of preferred wirelesscarrier identities, for communication in response to the mobile stationroaming to a predetermined market area.
 28. The apparatus of claim 27,wherein the database further comprises a plurality of home market areas,the generated list of preferred wireless carriers being based upon theselected class of service and a selected one of the plurality of homemarket areas.
 29. The apparatus of claim 27, wherein the databasefurther comprises a plurality of national accounts, the generated listof preferred wireless carriers being based upon the selected class ofservice and a selected one of the national accounts.
 30. A method forselecting a preferred wireless carrier for a mobile station to enablewireless communication when the mobile station is roaming outside of ahome market area of the mobile station, a database of preferred wirelesscarriers for a plurality of market areas based upon predeterminedclasses of service being provided at a predetermined location remotefrom the mobile station, a list of preferred wireless carriers beinggenerated based upon a selected class of service and the home marketarea of the mobile station, the list being stored in a storage deviceassociated with the mobile station designated with the selected class ofservice to enable a selection of a preferred wireless carrier band, themethod comprising:receiving, at the mobile station, a signal transmittedby a wireless carrier; determining whether the received signal istransmitted by a wireless carrier in the home market area of the mobilestation; and switching, based on the list in the storage device of themobile station, a communications band of the mobile station to apreferred wireless carrier band related to the roaming market area whenit is determined that the received signal is not transmitted by awireless carrier in the home market area of the mobile station.
 31. Anapparatus for selecting a preferred wireless carrier from a plurality ofwireless carriers for use by a mobile station when the mobile station isroaming outside of a home market area of the mobile station,comprising:a database of preferred wireless carriers for a plurality ofmarket areas based upon predetermined classes of service, predeterminednational accounts and predetermined home market areas; a generator thatgenerates a list of the preferred wireless carriers from the databasebased upon a selected class of service, a selected national account, aselected home market area of the mobile station; a data providing devicethat provides the generated list to the mobile station designated withthe selected class of service, the selected national account and theselected home market area; a memory, associated with the mobile station,that stores the generated list of preferred wireless carriers; and aselector, provided in the mobile station, that automatically selects apreferred wireless carrier from the list stored in the memory when themobile station is roaming and enters a market area of the plurality ofmarket areas.
 32. The apparatus of claim 31, wherein the list includesan alternative carrier for use in the event the preferred wirelesscarrier is not available to the mobile station.
 33. The apparatus ofclaim 31, wherein the data-providing device transmits the list ofpreferred wireless carrier identities to the mobile station by usingover-the-air programming.
 34. The apparatus of claim 31, wherein entriesof the generated list of preferred wireless carriers are prioritized,said memory of said mobile station truncating the generated list basedon the prioritized entries when a storage capacity of said memory isreached.
 35. A method for downloading a list of preferred wirelesscommunication bands stored in a database to a memory device of aplurality of mobile stations, the database containing the list ofpreferred wireless communication bands from which each mobile stationmay select a preferred wireless communication band when the mobilestation is roaming outside of a home market area of the mobile station,the database having a plurality of national account fields, a pluralityof home market area fields, and a plurality of class of service fields,each mobile station being assigned to a national account, a home marketarea and a class of service, the method comprising:determining when thelist of preferred wireless communication band stored in the memory ofeach mobile stations is outdated; determining, when the list isoutdated, if each mobile station is registered with a home locationregister; locating each mobile station and downloading an updated listto each mobile station when it is determined the mobile station isregistered with the home location register; and notifying a messagecenter when the mobile station is not registered with the home locationregister and, thereafter, downloading a new preferred wirelesscommunication band list to each mobile station when it is determined themobile station later registers with the home location register.
 36. Themethod of claim 35, wherein the downloading further comprises athrottling scheme which controls the number of mobile stations to whichthe downloading occurs during a predetermined period of time.